Consolidated 991RS thread
07-29-2014, 05:57 PM
#1126
Race Director
Not disagreeing with you about the weight difference or cost of larger diameter tires, TrackFan. But it seems obvious that, from a pure engineering and performance standpoint, Porsche sees an overall advantage to using 20 and 21" wheels over 19's or 18's. As I said earlier, whether the owner of the car agrees with their engineering choices when it comes time to buy new tires is another matter.
07-29-2014, 06:01 PM
#1127
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I'm seriously thinking of doing just that. I'm not happy with the direction Porsche is going.
07-29-2014, 06:10 PM
#1128
07-29-2014, 06:13 PM
#1129
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07-29-2014, 06:16 PM
#1130
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I have to disagree.. I believe branding and product differentiation are much greater values to Porsche and other manufacturers than what we naively believe. If Porsche decided that they wanted to differentiate the Rs more than in the previous generation, so that they can charge significantly more do the RS vs the gt3, then they need to find enough visual features to include to make this price delta worthy in a customer's eyes. mechanical matters also, but visual differentiation comes first because these are passion and impulse purchases. A "real" racer buys a stripped out fast car, the RS, let's be frank.. Treads that fine line between poseur and ultimate roadable track car.
If you agree with my statement above, then I would conclude that the 21" wheels and other features are added as long as they do NOT plausibly reduce performance, as long as the visual and brand differentiation outweighs the potential decrease in usability (21" R compound tires for example).
I realize this may not be a popular view, but I really think that as consumers we need to be a bit more critical and open eyed... We all know why there isn't a 3.8L cayman yet right?... All together now... MARKET SEGMENTATION!!!!!
So about that rear wing on the RS, I heard only the limited edition versions will be allowed in red.. Because red was tested to be a whole second faster around the 'ring ;-)
If you agree with my statement above, then I would conclude that the 21" wheels and other features are added as long as they do NOT plausibly reduce performance, as long as the visual and brand differentiation outweighs the potential decrease in usability (21" R compound tires for example).
I realize this may not be a popular view, but I really think that as consumers we need to be a bit more critical and open eyed... We all know why there isn't a 3.8L cayman yet right?... All together now... MARKET SEGMENTATION!!!!!
So about that rear wing on the RS, I heard only the limited edition versions will be allowed in red.. Because red was tested to be a whole second faster around the 'ring ;-)
IMHO, if one can evaluate a proposed change and objectively determine that there is no legitimate engineering or performance benefit to be derived, then it's safe to say that it's being done strictly for marketing segmentation or brand differentiation. Hence, ignition switches on the left side of the steering column.
But if there is a measureable difference in performance associated with a change, it becomes harder to say that it was done just for the sake of appearance. Going to a larger diameter wheel has provable benefits, so to say it's being done just for looks (I'm not personally struck by the visual difference between a 20 and 21) requires some of that cynicism I mentioned at the top.
As for the red wing being faster, well that's just science and an obvious no-brainer.
07-29-2014, 06:23 PM
#1131
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It may be hard to prove. Yes, the RS will be faster, but it has more HP, is lighter, and has more downforce.
We'll need someone to put on a 20" wheel, and see if it's slower.
Then i'd love to see the same test with 19" and 18" wheels.
We'll need someone to put on a 20" wheel, and see if it's slower.
Then i'd love to see the same test with 19" and 18" wheels.
07-29-2014, 06:30 PM
#1132
Race Director
Let's just say there are theoretical advantages to a larger diameter wheel. CAlexio will say I'm being naïve, but I'd like to think that Porsche and the guys who developed the new RS have done the legwork on proving which combination of wheels and tires works best. It would be silly for them to offer their new no-holds-barred super car with a sub-optimum wheel/tire package.
07-29-2014, 06:50 PM
#1133
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I'm harder to convince. It only has to work better than the GT3 to justify the price. It doesn't mean it couldn't work even better with a smaller wheel.
Porsche has two goals in life. Make money, and win races.
I look at what they do to the race cars more than the street cars, but that's where my interest is.
If it can be proven that going to a heavier taller tire has better performance than a smaller lighter one. I'll be the first to admit I was wrong.
Porsche has two goals in life. Make money, and win races.
I look at what they do to the race cars more than the street cars, but that's where my interest is.
If it can be proven that going to a heavier taller tire has better performance than a smaller lighter one. I'll be the first to admit I was wrong.
07-29-2014, 06:51 PM
#1134
Really? Have you tried tuning new turbo cars from manufacturers such as BMW or Mclaren recently? ECU is entirely locked down through encryption. No success in cracking them for years. Only options for "tuning" is through fairly arcane piggyback trickery. Additionally, with the complexity of hybrid systems, I would not trust some home brew mechanic to muck around with the cars.
07-29-2014, 07:03 PM
#1135
Rennlist Member
Thread Starter
Grip is everything, in dumbass world that means it's why a 3.8RS is faster on slicks even with the heaviest wheels than a 4.0 with superlight wheels on street tires. if bigger makes more grip is beterer My 0.02c
07-29-2014, 07:36 PM
#1137
Rules have limited race wheels to 18" only after Porsche won Le Mans with 20" wheels back in 1998. Thus this was "proven" in specific cases a long time ago.
Your only possible argument is that on this specific car larger wheels and tires are slower.
By saying that you're also saying that Porsche and other manufactures are intentionally leaving significant time on the table, ie the 918 lapped the 'ring in 6:57 with 21" wheels when it really could have gone, what, 6:50 with 18s? And the P1 would gain a few seconds too downsizing from 20s... How fast would the GT-R be on 18s, maybe it could catch the 918?
Porsche also intentionally over-sized wheels on its Le Mans racers, slowing them down and risking multi-million dollar investments, because in both cases making a slower car somehow helped them sell more cars. It's a vast conspiracy involving all manufactures, bigger and bigger wheels, slower and slower cars...
Or perhaps the uninformed simply see race cars on 18s and assume that's the fastest option, not realizing that it's the maximum size allowed under the rules. Not minimum size, by the way- Le Mans cars are free to run 17s and smaller if they want, but instead they chose to run 18s... until 2016 anyway, as there is a move to increase this size in the future.
07-29-2014, 07:43 PM
#1138
Racer
If the GT3 RS tires are the same size as the 918, maybe Porsche will offer the magnesium wheels that are available. Of coarse, at $32,500 (cost on 918) that would make for an expensive option. All the option prices on the 918 seem to be inflated so maybe they will offer them at a more reasonable cost on the RS. PCCBs and magnesium wheels would be a nice combo. Wishful thinking maybe.
07-29-2014, 07:56 PM
#1139
Rennlist Member
PeteV. Been asleep just catching up this morning. Thanks for your insight here. Its always great to have someone with an engineering background and real credentials comment - as stated in my earlier post Im no engineer! What you have explained makes alot of sense to me and I referenced it back to some of my literature on track driving (Ross Bentlys Speed Secretes etc) and it all checks out and makes sense. Tyre contact size and downforce all equate to grip and improved lap times. Infact my 993RS had much heavier wheels as factory supplied than the base model but they were 18s with a lrger OD than the stock 17s with smaller OD so that may in part answer a question re weight vs performance that I never could get the answer to. Durability was probably a factor too but the RS had more down force too as it had a rear fixed wing with large surface area....
Anyway, I digress but always good to have a debate and even better when we learn something and maybe get closer to the truth...always interesting to anticipate Porsches next move aye!
Anyway, I digress but always good to have a debate and even better when we learn something and maybe get closer to the truth...always interesting to anticipate Porsches next move aye!
07-29-2014, 07:59 PM
#1140
Rennlist Member
If the GT3 RS tires are the same size as the 918, maybe Porsche will offer the magnesium wheels that are available. Of coarse, at $32,500 (cost on 918) that would make for an expensive option. All the option prices on the 918 seem to be inflated so maybe they will offer them at a more reasonable cost on the RS. PCCBs and magnesium wheels would be a nice combo. Wishful thinking maybe.
Magensium may seem cool because its lighter but hi Mg wheels are way more prone to fracturing on the street/track and over time do not hold up so well - plus they need special etch primer when painted or lese will oxidise under the paint etc. Honestly, having gone there already with my 964RS (magnesium SM wheels) I wouldnt recommend it again for teh hassle...